OBJECTIVE: To investigate the pattern of changes in perceptual eye position in patients after Femtosecond Laser Small Incision Lenticule Extraction(SMILE), which was examined using the visual perception detection system developed by the National Engineering and Technology Research Center for Healthcare Appliances.
METHODS: A total of 141 patients participated in this prospective study. The patients were divided into three groups according to the degree of myopia: low myopic group
( equivalent spherical refraction ≤ 3.00D), moderate myopic group(3.00D < equivalent spherical refraction ≤ 6.00D), and high myopic group (equivalent spherical refraction > 6.00D). The relationship of perceptual eye position was measured by the computer-controlled visual perception detection system before, 1 day, 1 week and 1 month after surgery to investigate the changes of perceptual eye position after SMILE.
RESULTS: The differences in horizontal perceptual eye position were statistically significant at all time periods (X2=82.004, P<0.001), and the horizontal perceptual eye position improved at 1 day and 1 week postoperatively compared with that before surgery, but rebounded in January postoperatively. The differences in vertical perceptual eye position were statistically significant at all time periods (X2=38.59, P<0.001), and the vertical PEP improved at 1 day, 1 week, and 1 month postoperatively compared with the preoperative level, but the improvement was small. The difference between horizontal perceptual eye position and vertical perceptual eye position in all three groups was not statistically significant, and it can be concluded that the deviation of perceptual eye position after SMILE is not related to the degree of myopia.
CONCLUSION: Most myopic patients have perceptual eye position shift before refractive correction, and SMILE surgery can improve the perceptual eye position shifts significantly in the early postoperative period, but the long-term results need to be further observed.